16573

This program is a recurring UVIS calibration monitor that will observe two stellar clusters (Omega Centauri comma and 47 Tuc) to measure the flux loss of point sources as a function of detector row number due to degrading Charge Transfer Efficiency (CTE). Because CTE fluctuates with characteristics such as source flux and background level comma this program is designed to take short and long exposures comma at various commanded post-flash levels with the F502N filter. We will compare the results from these new observations with previous external CTE calibration programs and update the aperture phometry-based CTE model. Furthermore comma ACS has an external CTE calibration program that observes NGC 104 at various post-flash levels that can also be used for direct comparison. Lastly comma these data will be used to help monitor-improve the empirical pixel-based CTE correction (FLC-DRC).